1. Field of the Invention
This invention is generally related to earth working or excavating equipment and more specifically to covers for cooperatively and selectively engaging with and sealing the opening or mouth of conventional backhoe and clam-shell buckets to thereby prevent the accidental discharge or spillage of any material excavated or dredged using such equipment. The covers may either be fixedly located so as to be engaged by the buckets when the buckets assume a closed or fully scooped position or may be selectively movable so as to permit relative movement of the covers with respect to an associated bucket. In the preferred embodiment, the covers are structured so as to be flexible and expandable relative to the bucket so that any material which has been excavated but which extends above the opening in the buckets will be closed in the expanded covers.
2. History of the Related Art
Inland and coastal waterways are continuously being threatened by increases or buildups of waste and sludge deposits as well as natural increases in siltation. Soil deposits not only clog water channels threatening or restricting navigational passage but also adversely affect the quality of water by creating concentrated areas of contaminants and pollutants. As our society continues to grow and expand, it is paramount that the environmental soundness and quality of our waterways and water recreational areas be maintained and preserved. This requires the removal or dredging of our waterways to remove waste and sludge deposits and natural and man made sedimentations.
To date, dredging operations have been accomplished by mechanical digging debris and sedimentations, by pumping lose or fine sedimentations from subsurface areas or by combinations of earth working and pumping. In those areas where the deposits or sedimentations include toxic or hazzardous wastes including chemical concentrations from manufacturing or processing plants or chemical run-offs from locally fertilized lands, the deposits or sedimentations must be carefully handled and transported and/or treated to permit their safe disposal. Unfortunately, conventional dredging and earth working equipment has not been designed to adequately handle waste removals without creating additional problems such as releasing loose sedimentation into downstream flows as wastes and other materials are scooped and lifted from subsurface areas.
When dredging or digging using bucket type earthworking equipment including backhoe, extendable boom mounted buckets and clam-shell buckets, large quantities of earth, silt, debris, rocks, etc., may be raised with each scoop. However, as such material is lifted, the excess materials above and within the open rims of the buckets are often dislodged. In underwater dredging operations, the excess materials excavated with each scoop of a conventional bucket are often dislodged and entrained in the water thereby adversely increasing the turbidity of the water or causing such materials to be deposited into downstream areas. In instances where potentially hazardous or toxic materials are being dredged, any realease of solid materials away from the dredging site is totally undesirable and potentially unhealthful for those areas to which such materials may be transported or conveyed.
To date, no one has developed a system or equipment to permit adequate handling of excavated waste materials and especially dredged waste materials without creating further waste spillage, release or distribution of the materials being handled. In U.S. Pat. No. 3,807,539 to Shovick, a supplemental bucket is shown as being used with a conventional backhoe bucket so as to create an implement which will have opposing portions which will operate as jaws to grasp material or to substantially entrap material therebetween. The supplemental or auxiliary bucket is fixedly secured to the backhoe dipper stick adjacent the conventional bucket. The edges of the auxiliary bucket are further designed to be complimentary to the edges of the conventional bucket when the conventional bucket reaches a full closed position with respect thereto. Unfortunately, if such a bucket arrangement were utilized in the dredging or digging of contaminated waste, loose material would be dislodged or discharged from between the two buckets as they close with respect to one another. Also, although the edges of the buckets are complementary in shape, they do not seal with respect to one another so material may pass from therebetween during use, and especialy during use in an underwater environment.
In U.S. Pat. No. 3,737,059 to Peterson et al., another combination earth working bucket is disclosed wherein each of auxiliary and primary buckets is selectively pivotally movable with respect to the opposing bucket. As with the aforesaid patent to Shovick, the combination bucket of Peterson, et al., is also not adequately designed to use in excavating contaminated or waste debris especially in aqueous environments without allowing a substantial portion of the material being excavated from being spilled and entrained in the surrounding waterway. The operation of the Peterson, et al. structure is similar to a conventional clam-shell type bucket and therefore the top of the auxiliary bucket is opened. Collected materials could therefore be washed from or overflow from the opened structure when the bucket is being filled with material. Further, the interface between the bucket components is not sealed so that materials may also pass between the opposing edges of the buckets when in use.
Some additional examples of multi-componented excavation buckets include U.S. Pat. Nos. 3,003,265 to Lutjens and 3,477,602 to Peterson.